U.S. patent number 5,638,896 [Application Number 08/522,415] was granted by the patent office on 1997-06-17 for cold-hot storage box with inert gas insulating jacket.
This patent grant is currently assigned to Nippon Sanso Corporation. Invention is credited to Seiichi Ito, Kunio Matsuda, Yoshiya Nishino, Masashi Yamada.
United States Patent |
5,638,896 |
Nishino , et al. |
June 17, 1997 |
Cold-hot storage box with inert gas insulating jacket
Abstract
The present invention relates to a cold-hot storage box which
can be used as a constant temperature box, a refrigerator for
household use, or a freezer, and to a manufacturing method
therefor. The cold-hot box of the present invention being
characterized by the provision of an insulating container
comprising a space of a double walled container made from an inner
container and an outer container, enclosing at least one gas having
low thermal conductivity selected from the group consisting of
xenon, krypton, and argon.
Inventors: |
Nishino; Yoshiya (Tokyo,
JP), Matsuda; Kunio (Tokyo, JP), Yamada;
Masashi (Tokyo, JP), Ito; Seiichi (Tokyo,
JP) |
Assignee: |
Nippon Sanso Corporation
(Tokyo, JP)
|
Family
ID: |
11792642 |
Appl.
No.: |
08/522,415 |
Filed: |
September 20, 1995 |
PCT
Filed: |
January 24, 1995 |
PCT No.: |
PCT/JP95/00074 |
371
Date: |
September 20, 1995 |
102(e)
Date: |
September 20, 1995 |
PCT
Pub. No.: |
WO95/21361 |
PCT
Pub. Date: |
August 10, 1995 |
Foreign Application Priority Data
Current U.S.
Class: |
165/132;
62/457.1; 62/3.6; 62/372 |
Current CPC
Class: |
F25D
23/062 (20130101) |
Current International
Class: |
F25D
23/06 (20060101); F28D 001/06 () |
Field of
Search: |
;62/457.1,457.2,457.7,457.9,3.6,440 ;165/132,DIG.342,DIG.354
;220/421,420,425,426 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
848292 |
|
Oct 1939 |
|
FR |
|
38-8678 |
|
May 1963 |
|
JP |
|
49-18303 |
|
May 1974 |
|
JP |
|
58-49186 |
|
Apr 1983 |
|
JP |
|
2-3080 |
|
Jan 1990 |
|
JP |
|
3-18478 |
|
Mar 1991 |
|
JP |
|
Primary Examiner: Sollecito; John M.
Attorney, Agent or Firm: Fish & Richardson P.C.
Claims
We claim:
1. A cold-hot storage box comprising:
an insulating container formed into a box having an opening, said
container having a double walled structure made from an inner
container and an outer container which are unitarily joined so as
to maintain a space therebetween as an insulation layer;
an insulating lid having a double walled structure made from an
outer panel and an inner panel which are unitarily joined so as to
maintain a space therebetween as an insulation layer;
and a heat exchange means which controls the temperature in said
insulating container;
wherein an insulating lid can be freely opened and closed and is
attached to edge portions of said opening of said insulating
container;
wherein at least one gas having low thermal conductivity selected
from the group consisting of xenon, krypton, and argon is enclosed
in the space provided in said insulating container and lid
respectively; and
wherein a gas injection pipe is sealed at its tip and connected to
said insulation layer and a knob which covers said gas injection
pipe is provided on said lid.
2. A cold-hot storage box as recited in claim 1, wherein said gas
injection pipe is made from synthetic resin material and its tip is
hermetically sealed by an adhesive.
3. A cold-hot storage box comprising:
an insulating container formed into a box having an opening, said
container having a double walled structure made from an inner
container and an outer container which are unitarily joined so as
to maintain a space therebetween as an insulation layer;
an insulating lid having a double walled structure made from an
outer panel and an inner panel which are unitarily joined so as to
maintain a space therebetween as an insulation layer;
and a heat exchange means which controls the temperature in said
insulating container;
wherein an insulating lid can be freely opened and closed and is
attached to edge portions of said opening of said insulating
container;
wherein at least one gas having low thermal conductivity selected
from the group consisting of xenon, krypton, and argon is enclosed
in the space provided in said insulating container and lid
respectively; and
wherein evacuation apertures are provided in a recessed manner in
said insulating container and lid, indented portions are provided
around the edges of said evacuation apertures, and said evacuation
apertures are closed up by sealing plates joined by means of an
adhesive into said indented portions.
Description
TECHNICAL FIELD
The present invention relates to a cold-hot storage box which can
be used as a constant temperature box, a refrigerator for household
use, or a freezer, and to a manufacturing method therefor.
BACKGROUND ART
Generally, cold-hot storage boxes have a box shaped insulating
container having an opening, a lid which is freely opened and
closed attached to the edge portion of the opening of this
insulating container, and a heat exchange apparatus which is
attached to at least one of the lid and the insulating container.
These insulating container and lid are manufactured using an
insulating material. In some cases, as the aforementioned heat
exchange apparatus, an electric cooling element, such as a Peltier
element, is used. In this Peltier element, heat generation or
absorption occurs at contact points by means of connecting
different types of conductors or semiconductors and running a
direct electric current; one conductor or semiconductor cools, and
the other different conductor or semiconductor warms. This is
believed to be a phenomenon that occurs because the ratio of the
heat flow and electric flow carried by free electrons is not equal
on both sides of the conductor or semiconductor. In addition, if
the direction of the flow of the direct electric current is
reversed, heat generation and absorption become reversed. To
improve the temperature maintaining ability of this kind of
cold-hot storage box, not only are improvements necessary in the
heat exchange ability of the Peltier element, but improvements in
the insulating ability of the insulating material are also
necessary.
In addition, ordinary refrigerators comprise an insulating
container, piping arranged inside this insulating container, a
refrigerant gas which flows in this piping, a gas liquefying means
for liquefying this refrigerant gas, and a vaporizer for vaporizing
this refrigerant gas. In this refrigerator, a refrigerant gas, such
as Freon or the like, is condensed or compressed and liquefied by
the gas liquefying means; subsequently, the refrigerant gas absorbs
the heat of vaporization from inside the insulating container by
means of vaporization by the vaporizer, and the inside of the
insulating container is cooled. This kind of refrigerator
insulating container uses insulation materials.
However, in the insulation materials used by these insulating
containers, because foam materials, such as foam urethane, foam
styrene, or the like, are used, it is necessary for the thickness
of the insulation to be thickly formed so that the insulation has
sufficient insulating ability. In particular, when using foam
urethane as insulating material, at production time, in order to
completely fill the insulation layer with the insulation material,
considerable thickness and pressure are needed; thin insulation
layers of several millimeters are difficult to manufacture. The
ratio between the capacity of the exterior and the storage capacity
(inner capacity), in other words, the volumetric capacity, for the
resulting insulating container, has the problem that it is low.
In addition, at the time of manufacture of the insulating
container, if the foaming does not happen with sufficient control
of the pressure, quantity of foam material, etc., the foam urethane
does not spread completely, places of inferior insulation arise,
and there is the risk that the insulating ability will be reduced.
Furthermore, in some cases, Freon, which causes damage to the ozone
layer, is used as a foaming material, and this is not desirable
from the point of view of the environment.
On the other hand, in some cases, vacuum insulation is used to
improve the insulating ability of the insulating material. In this
vacuum insulation, the insulating ability of the insulation
material is improved, but production costs become high.
Furthermore, in the case of vacuum insulation, a sufficient bearing
strength is necessary in the insulating container as the load of
atmospheric pressure bears upon the insulating container, and there
is a problem with limitations on the shape of the insulating
container so that the bearing strength can be obtained.
DISCLOSURE OF INVENTION
The invention of the present application provides, as an object, a
cold-hot storage box which is superior in insulating ability and
volumetric capacity; moreover, its manufacturing costs are low, and
it can be formed into any kind of shape desired.
The cold-hot storage box of the present application is a cold-hot
storage box having an insulation container which is a double walled
container made from an inner container and an outer container which
are unitarily joined so as to maintain a space therebetween as an
insulation layer; and a heat exchange means which controls the
temperature in the insulating container; the cold-hot storage box
characterized in that at least one gas having low thermal
conductivity selected from the group consisting of xenon, krypton,
and argon is enclosed in said space.
In the cold-hot storage box of the present invention, the structure
can be such that the aforementioned insulating container is formed
into a box shape having an opening, and an insulating lid which can
be freely opened and closed attached to the edge portion of the
opening of this insulating container.
In addition, the structure can be such that a gas injection pipe
sealed at its tip and connected to the aforementioned space is
provided in the aforementioned insulation container. In addition,
the structure can be such that the gas injection pipe is made from
synthetic resin, and its tip is hermetically sealed by an
adhesive.
In addition, the structure can be such that an insulation layer
filled with the aforementioned gas having low thermal conductivity
is provided in the aforementioned lid. In addition, the structure
can be such that a gas injection pipe sealed at its tip and
connected to the insulation layer is provided in this lid.
Furthermore, the structure can be such that the gas injection pipe
is made from synthetic resin material and its tip hermetically
sealed by an adhesive.
In addition, the structure can be such that evacuation apertures
are provided in a recessed manner in the aforementioned insulating
container and lid, the aforementioned gas having low thermal
conductivity is enclosed in the space provided in said insulating
container and lid respectively, and the aforementioned evacuation
apertures closed up by sealing plates. Furthermore, the structure
can be such that indented portions which will fit the sealing
plates are provided around the edges of the aforementioned
evacuation apertures, and the sealing plates fitted into these
aforementioned indented portions joined by adhesive.
In the cold-hot storage box of the present invention, the structure
can be such that the aforementioned insulation layer is
multilaminated.
In addition, in the cold-hot storage box of the present invention,
the structure can be such that the aforementioned heat exchange
means is provided with an electric cooling element, such as a
Peltier element; a temperature measuring means for measuring the
temperature of the inside of the insulating container; and a
control means for controlling the quantity of electric current to
the electric cooling element in accordance with data from the
aforementioned temperature measuring means.
In the cold-hot storage box of the present invention, the structure
can be such that metallic membranes are provided on the inner
surface of the aforementioned outer container and the outer surface
of the aforementioned inner container.
The manufacturing method for the cold-hot storage box of the
present invention, is a method for manufacturing a cold-hot storage
box having: an insulation container which is a double walled
container made from an inner container and an outer container which
are unitarily joined so as to maintain a space therebetween as an
insulation layer; and a heat exchange means which controls the
temperature in the aforementioned insulating container,
characterized by:
(a) a step of accommodating the aforementioned inner container in
the aforementioned outer container by unitarily joining the
aforementioned inner container to the inside of the aforementioned
outer container while maintaining the space to produce a double
walled container having a sealable ventilation aperture;
(b) a step of vacuum evacuating the inside of the aforementioned
space through the aforementioned evacuation aperture while
adjusting the pressure of the surroundings of the double walled
container in such a way that the pressure difference between the
surroundings of the double walled container and the aforementioned
space of the double walled container become small; and
subsequently, injecting at least one gas having low thermal
conductivity selected from the group consisting of xenon, krypton,
and argon in the inside of the aforementioned space through the
aforementioned ventilation aperture; and
(c) a step of hermetically sealing the aforementioned ventilation
aperture and enclosing the gas having low thermal conductivity
inside the space to form the insulation layer.
The aforementioned sealable ventilation aperture can be an
evacuation aperture which can be hermetically sealed by means of
joining a sealing plate, or a gas injection pipe provided on the
outer container.
The cold-hot storage box of the invention of the present
application, being constructed such that it is provided with an
insulating container comprising a space of a double walled
container which has been filled with at least one gas having low
thermal conductivity selected from the group consisting of xenon,
krypton, and argon, gives rise to no unevenness in the insulating
ability of the insulating layer, when compared with conventional
goods equipped with an insulating layer made from insulating
materials; moreover, since the insulating ability of the insulating
layer is particularly superior, the insulating ability of the
insulating container can be greatly improved. Furthermore, since
foam materials using Freon gas which has a damaging effect on the
ozone layer are not used, this is desirable from the point of view
of the environment. In addition, with regard to the insulation
layer filled with gas having low thermal conductivity, since the
insulating ability is particularly superior, the volumetric
capacity can be improved
In addition, when compared with conventional products which use
vacuum insulation, because manufacturing can be accomplished by
means of easy formation and processing of synthetic resin
materials, and because the manufacturing processes are simple, the
manufacturing costs of the insulating container can be reduced. In
addition, in this insulating container, since the space between
inner and outer container is filled with a gas having low thermal
conductivity, it is possible to set the bearing pressure of the
container lower in comparison to vacuum insulation, and it becomes
easy to form various shapes, in particular, box shapes which have
flat wall portions and which cause manufacturing problems for
conventional goods of vacuum insulation methods.
In addition, in the manufacturing method for the cold-hot storage
box of the present invention, when the inside of the space of the
double walled container is vacuum evacuated, and then filled up
with the gas having low thermal conductivity, because the pressure
of the surroundings of the double walled container is adjusted
while the evacuation and the injection of the gas having low
thermal conductivity takes place, in such a way that the difference
in the pressure of the space and the pressure of the surroundings
of the double walled layer is small, the necessary bearing strength
of the inner container and the outer container can be set smaller.
As a result, it is not necessary to form the shape of the inner
container and the outer container into structures, such as spheres,
or cylinders, which are good at withstanding pressure, and it is
therefore possible to manufacture cold-hot storage boxes in any
shape. In addition, since the necessary bearing pressure of the
inner container and the outer container can be set low, the walls
of the insulating container and the walls of the lid can be set
fairly thin, and it is possible to manufacture a light weight
cold-hot storage box which is suitable for portable use, and
moreover has a highly efficient volumetric capacity.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partially cut away frontal view showing an embodiment
of the cold-hot storage box of the present invention.
FIG. 2 is an enlarged drawing of the section X of the first
drawing.
FIG. 3 is an enlargement of the section X showing an alternative of
the metallic membrane shown in the second drawing.
FIG. 4 is an enlargement of the section X showing an alternative
example of an insulation layer divided by a dividing material.
FIG. 5 is a partially cut away frontal view showing another example
of the cold-hot storage box of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
The cold-hot storage box and manufacturing method of Example 1 of
the present invention will be explained in detail with reference to
FIG. 1. In FIG. 1, 1 is a cold-hot storage box. This cold-hot
storage box 1 possesses an insulating container 2 and a heat
exchange means 20 for controlling the temperature of the inner
portion of insulating container 2. This insulating container 2 has
an inner container 3, an outer container 4, which is arranged
surrounding inner container 3, metallic membranes 31 and 32, formed
on mutually opposing respective surfaces of inner container 3 and
outer container 4, and a gas, which fills a space 5 of mutually
opposing metallic membranes 31 and 32. Inner container 3 and outer
container 4 are unitarily joined at their peripheral edges forming
a double-walled container, and an insulation layer 6 is formed by
enclosing a gas having low thermal conductivity in the space 5
between inner container 3 and outer container 4. The thickness of
the insulation layer 6 is such that it is difficult for the gas
having low thermal conductivity to circulate, the preferable
aforementioned thickness being in a range of 1.about.10 mm.
Insulating container 2 is formed from a synthetic resin such as ABS
resin, or a metallic material such as stainless steel. It is
possible for inner container 3 and outer container 4 to be composed
of the same kind of materials, or they can be made of different
kinds of materials. The insulating container 2 made from unitarily
joining inner container 3 and outer container 4 has a box shaped
opening 7 in its side, and a door (lid) 10 which can be freely
opened and closed is fitted into the edge portions of opening
7.
Door 10 can be made from synthetic resin such as ABS resin, or a
metallic material. Door 10 has an outer panel 11 which is exposed
to the outside; an inner panel 12 which is arranged facing outer
panel 11; metallic membranes on the surfaces of mutually opposing
outer panel 11 and inner panel 12, arranged in the same way as the
metallic membranes 31 and 32 of the insulating container 2; and a
gas having low thermal conductivity which fills a space 13 between
outer panel 11 and inner panel 12. Outer panel 11 and inner panel
12 are unitarily joined at their peripheral edges forming a double
walled structure, and by filling space 13 with gas, an insulation
layer 14 is formed.
To the outer container 4 of insulating container 2 and the outer
panel 11 of the door 10, gas injection pipes 8 and 15 are
connected, respectively, so that spaces 5 and 13 can be filled with
gas having low thermal conductivity and sealed. Gas injection pipes
8 and 15 are hermetically sealed at their tips, and are made from
synthetic resin material such as ABS resin, or metallic materials,
in the same way as insulating container 2. When aforementioned gas
injection pipes 8 and 15 are made from synthetic resin, the tips of
gas injection pipes 8 and 15 can be unitarily joined and
hermetically sealed, preferably using a synthetic resin adhesive
such as epoxy resin (for example, the product Araldite manufactured
by Ciba Geigy), or a sealing method such as heat welding. In
particular, to reduce gas penetration, use of a synthetic resin
adhesive of an epoxy type to seal the tips of gas injection pipes 8
and 15 is preferable. In that case, the gas injection pipes 8 and
15 can be filled with synthetic resin adhesive and hermetically
sealed, the inside of gas injection pipes 8 and 15 can be coated
with synthetic resin adhesive, and the gas injection pipes 8 and 15
can be hermetically sealed by pressure. In addition, when gas
injection pipes 8 and 15 are made from a metal material, it is
preferable that they be unitarily joined by welding or the like,
respectively, to outer container 4 and outer panel 11.
Gas injection pipe 8 of insulating container 2 is positioned in the
vicinity of heat exchange means 20, and gas injection pipe 15 of
door 10 is positioned in the center of the side edge of outer panel
11. The gas injection pipe 15 of door 10 is covered by a knob
(cover) 16.
FIG. 2 shows the metallic membranes 31 and 32 formed on insulating
container 2. The metallic membranes 31 and 32 of insulating
container 2, and the same metallic membranes of door 10 are formed
by a method of one of vacuum deposition, plating, and adhesion of
metallic foil. These metallic membranes 31 and 32 prevent gas
permeation, and prevent the radiation of heat. By surrounding the
gas having low thermal conductivity with these metallic membranes,
the gas having low thermal conductivity is prevented from leaking
out. In addition, as shown in FIG. 3, in place of metallic
membranes 31 and 32, metallic foil 33 can be arranged between inner
container 3 and outer container 4.
As a gas having low thermal conductivity, an inert gas having a
heat conductivity lower than air, such as xenon, krypton, argon, or
the like, or a mixture of these gases, can be used. At 0.degree.
C., the thermal conductivity of air (.kappa.) is
2.41.times.10.sup.2 W.multidot.m.sup.-1 .multidot.K.sup.-1, in
contrast, xenon has a thermal conductivity of 0.52.times.10.sup.2
W.multidot.m.sup.-1 .multidot.K.sup.-1, krypton has a thermal
conductivity of 0.87.times.10.sup.2 W.multidot.m.sup.-1
.multidot.K.sup.-1, and argon has a thermal conductivity of
1.63.times.10.sup.2 W.multidot.m.sup.-1 .multidot.K.sup.-1. In
addition, these gases, unlike Freon gas, do not cause damage to the
ozone layer, and their use is desirable for the preservation of the
environment.
The injection pressure of the gas having low thermal conductivity
is in a range from 600 to 760 mmHg at room temperature
(20.degree..about.30.degree. C.).
Heat exchange means 20 has an electric cooling element 21, such as
a Peltier element; a temperature measuring means for measuring the
temperature of the inside of insulating container 2; and a
controlling means 25 for controlling the flow of electric current
to cooling element 21 in accordance with the data from the
aforementioned temperature measuring means. Electric cooling
element 21 is made from a conductor or a semiconductor, and has a
heat radiating portion 22 arranged on the outside of insulating
container 2, and a heat absorbing portion 23, which is made from a
different kind of conductor or semiconductor from that used to make
heat radiating portion 22, connected to the heat radiating portion
22 and arranged on the inside of insulating container 2. In
electric cooling element 21, heat absorbing portion 23 is cooled
and heat radiating portion 22 is warmed by means of the flow of
direct electric current. In addition, in the vicinity of heat
radiating portion 22, a cooling fan 24 is arranged which blows cool
air onto heat radiating portion 22. As the aforementioned
temperature measuring means, a thermocouple, commercially available
temperature sensor, or the like can be used.
The heat exchange means 20 is mounted on the upper part of
insulating container 2, and is covered by cover 26 which is
integrated with outer container 4. The electric cooling element 21
of heat exchange means 20 is arranged so that it communicates with
the inside of the container through an opening in part of
insulating container 2. Furthermore, heat exchange means 20 is
attached to insulating container 2, but it can also be attached to
door 10.
By means of running a direct electric current to electric cooling
element 21, heat exchange means 20 absorbs heat from the inside of
insulating container 2 by heat absorbing portion 23, and this heat
is radiated away by heat radiating portion 22. In this case, the
heat radiating effect of heat radiating portion 22 can be improved
by the action of cooling fan 24.
In addition to the aforementioned use as a cold storage box,
cold-hot storage box 1 can be used as a hot storage box by
reversing the direction of the direct electric current flow in
electric cooling element 21, making heat absorbing portion 23 a
heat radiator which can then keep the inside of the container warm.
Furthermore, if the cold-hot storage box 1 is organized in such a
way that the flow of direct electric current can be suitably
switched, the container can be used as a constant temperature
container in which cooling occurs when the temperature of the
inside of the container rises above a fixed temperature, and
heating occurs when the temperature inside the container falls
below a fixed temperature.
In addition, in the aforementioned example, an example is shown in
which insulation layer 6 of insulating container 2 and insulation
layer 14 of door 10 are, respectively, single layers; however, a
multilaminated structure for insulation layers 6 and 14 is also
possible. FIG. 4 shows an example in which layer 6 is divided into
a plurality of layers by providing a dividing material 40 in
between inner container 3 and outer container 4 of insulating
container 2. Dividing material 40 can be formed from a thin panel
made from a metal, synthetic resin, or the like, and metallic
membranes 41 and 42, which are the same as the metallic membranes
31 and 32 of insulating container 2, are formed on both surfaces of
dividing material 40. Insulation layer 6 is divided by arranging
dividing material 40 in between inner container 3 and outer
container 4, by making insulation layer 6 and 14 multilaminated
structures, it is possible to improve the heat insulating ability
of insulation layers 6 and 14 so that an insulating ability equal
to vacuum insulation can be obtained.
In the following, the manufacturing method of the aforementioned
cold-hot storage box 1 will be explained.
In manufacturing cold-hot storage box 1, insulating container 2 and
door 10 are manufactured first. With regard to insulating container
2, a metallic membrane is formed by means of a vacuum deposition
method, a galvanizing (chemical galvanizing, or electrical
galvanizing) method, a metallic foil adhesion method, or the like
on to the inner surface of outer container 4 and the outer surface
of inner container 3, which are composed of synthetic resin or the
like. Then, the peripheral edges of inner container 3 and outer
container 4 are joined by means of soldering, adhesion by an
adhesive, welding, or the like, forming an integrated unit with a
space 5 between inner container 3 and outer container 4. Then the
integrated double walled container formed from inner container 3
and outer container 4 is put into a chamber.
In this chamber, the air in the chamber and the air inside the
space 5 of the double walled container is evacuated. At this time,
the pressure is reduced in such a way that excessive force is not
exerted on the double walled container, and the difference in the
pressure between the pressure inside the chamber and the pressure
inside space 5 of the double walled container is made small.
Subsequently, when the air pressure inside the chamber reaches
about 1/10 of an atmosphere, the vacuum evacuation of the chamber
is terminated. In addition, the vacuum evacuation of the space 5 of
the double walled container continues, and after the pressure in
space 5 reaches the neighborhood of about 10 mmHg, the vacuum
evacuation of space 5 is terminated.
Next, space 5 of insulation layer 6 is filled to a predetermined
pressure with xenon gas, or the like, from a gas supply tank. At
this time, the difference in the pressure between the pressure
inside insulation layer 6 and the pressure in the chamber is kept
small so that excessive force is not exerted on the double walled
container, and while the pressure inside the chamber is gradually
returned to atmospheric pressure, insulation layer 6 is filled up
with a gas having low thermal conductivity to an injection pressure
at a level of 600 to 760 mmHg. When the inside of the chamber has
been opened to atmospheric pressure, the gas injection pipe 8,
positioned on outer container 4, is hermetically sealed by adhesive
filler, pressure, welding, or similar method, thereby forming
insulating container 2. After this, the insulating container 2 is
removed from the chamber.
By the aforementioned processes, insulation container 2 which has
been injected with an inert gas having low thermal conductivity, in
which thermal conductivity is small, is produced.
Door 10 is manufactured in the same way as the aforementioned
insulating container 2. The outer panel 11 and inner panel 12 of
door 10 are prepared, and a metallic membrane is formed on the
inner surface of outer panel 11 and on the inner surface of inner
panel 12 by means of the same method as that used for the
aforementioned inner container 3 and outer container 4, and after
the peripheral edges of outer panel 11 and inner panel 12 are
joined and integrated, put into a chamber. In this chamber, while
the pressure around door 10 is reduced in such a way that excessive
pressure is not exerted on door 10, space 13 of door 10 is
evacuated. After this, space 13 is filled with a gas having low
thermal conductivity through gas injection pipe 15 of door 10, and
the pressure of the surroundings of door 10 are gradually returned
to atmospheric pressure. Next, gas injection pipe 15 of door 10 is
hermetically sealed and door 10 is taken out of the chamber.
In this way, the container 2 and door 10 are constructed, and by
mounting heat exchange means 20 onto insulating container 2, the
cold-hot storage box 1 is manufactured.
As cold-hot storage box 1 is provided with an insulating container
2, wherein space 5 of the double walled container is filled with at
least one gas having low thermal conductivity selected from the
group consisting of xenon, krypton, and argon, even when inner and
outer container 3 and 4 are made from synthetic resin or the like,
the joining portions of inner and outer container 3 and 4 can be
prevented from being dissolved by organic gases such as Freon gas.
Consequently, inner and outer container 3 and 4 can be manufactured
from synthetic resin using simple formation processes, inner and
outer container 3 and 4 can be safely maintained, and the
construction costs of inner and outer container 3 and 4 can be
reduced.
In addition, in insulating container 2, since a gas having low
thermal conductivity is injected into the space 5 of the double
walled container, the production of unevenness in the insulating
ability of the insulation layer is prevented when compared to
insulating containers which use existing insulation materials.
Furthermore, since foam materials which use Freon which has a
damaging effect on the ozone layer are not used, insulation
container 2 is good for the environment. In addition, since foam or
the like is not injected, the insulation layers need not be thick
and can be thinly shaped, and the volumetric capacity of insulating
container 2 can be increased.
In addition, when compared to the existing vacuum insulation
methods, the manufacturing processes are simple, and because
manufacturing can be done by simple formation and processing of
synthetic resin materials, manufacturing costs can be reduced. In
addition, since a gas having low thermal conductivity has been
injected in the space 5 of the double walled container structure of
insulating container 2, the pressure bearing strength of the
container can be lowered compared with vacuum insulated containers,
making it easy for the container to be formed into various shapes,
in particular, box shapes having flat walled sections are
possible.
Furthermore, since metallic membranes 31 and 32 for preventing both
heat radiation and gas penetration have been formed on the inner
surface of outer container 4 and the outer surface of inner
container 3, steam, oxygen gas, nitrogen gas, and the like cannot
infiltrate insulation layer 6, and the gas having low thermal
conductivity cannot leak out of insulation layer 6, thus the gas
having low thermal conductivity of insulation layer 6 can be
maintained for long periods. By having basically the same structure
as insulating container 2, door 10 also yields the same results as
insulating container 2. Consequently, this cold-hot storage box 1
can maintain a superior insulating ability for long periods.
In addition, in the aforementioned manufacturing method for
cold-hot storage box 1, when the pressure inside space 5 of
insulating container 2 is reduced, the pressure surrounding
insulating container 2 is adjusted so that the difference in the
pressure between the pressure in space 5 and the pressure
surrounding container 2 is made small; and the difference between
the inner pressure and the outer pressure exerted on the walls of
inner container 3 and outer container 4 can be made small, thereby
making it possible to reduce the necessary bearing pressure for
inner container 3 and outer container 4. As a result, it is not
necessary to form inner container 3 and outer container 4 into
structures which are good for withstanding pressure, such as
spheres, or cylinders, and it is possible to manufacture cold-hot
storage box 1 in any shape. In addition, since the necessary
bearing pressure of inner container 3 and outer container 4 can be
set low, the walls of insulating container 2 and the walls of door
10 can be made thin, making it possible to manufacture a light
weight cold-hot storage box which is suitable for portable use and
has a highly efficient volumetric capacity.
Manufacturing Example
Inner container 3 and outer container 4 of insulating container 2
were made using ABS resin, and onto the outer surface of inner
container 3 and the inner surface of outer container 4, a copper
galvanizing layer several micrometers thick was formed by means of
an electric galvanizing process. Insulating container 2 was made by
joining the peripheral edges of inner container 3 and outer
container 4 with epoxy resin. This insulating container 2 was put
into a chamber, gas injection pipe 8 provided on outer container 4
and the evacuation opening of the chamber were connected to a
vacuum pump, the pressure inside space 5 of insulating container 2
and inside the chamber were reduced to 100 mmHg, and the evacuation
of the chamber was terminated. Then, the pressure inside of space 5
of insulating container 2 was further evacuated to 0.1 mmHg. After
the inside of space 5 had been evacuated to 0.1 mmHg, xenon gas was
introduced into space 5 while the pressure of the inside of the
chamber was gradually returned to atmospheric pressure. The filled
pressure of the xenon of space 5 was 700 mmHg.
After the pressure of the chamber had been returned to atmospheric
pressure, the gas injection pipe 8 of insulating container 2 was
welded closed using an ultrasonic welder, the xenon gas enclosed in
space 5 forming insulation layer 6, and the obtained insulating
container 2 was taken out of the chamber.
The temperature maintaining ability of the manufactured insulating
container 2 was compared with that of a conventional product which
possessed foam urethane as an insulation layer and the results
measured. When compared, it was confirmed that insulating container
2, with an insulation layer 6 about 1/3 the thickness of the
conventional product, possessed the same temperature maintaining
ability as the conventional product.
In addition, since the heat resistance of the foam urethane itself
is low, foam urethane can only be used for cold-maintaining
containers; however, since the insulating container 2 of the
cold-hot storage box 1 obtained by means of the aforementioned
manufacturing example uses synthetic resin materials which have
high heat resistance, it is not limited to use as a cold
maintaining container only, it can also be used as a
temperature-maintaining container for maintaining the temperature
of boiling water or the like.
In addition, door 10, by having the same structure as insulating
container 2, and by being made by means of the same manufacturing
method, obtains the same excellent heat maintaining ability and
heat resistance as does the aforementioned insulating container
2.
FIG. 5 shows another example of the cold-hot storage box of the
present invention. In this example, cold-hot storage box 1B is
constructed possessing almost the same structural elements as the
cold-hot storage box 1 shown in FIG. 1; those structural elements
which are the same have the same number and explanation thereof
will be omitted. In the cold-hot storage box 1B of this example,
for the purpose of hermetically sealing insulating container 2 and
door 10, evacuation apertures 34 and 36 are provided in a recessed
manner in outer container 4 of insulating container 2 and outer
panel 11 of door 10, respectively. These evacuation apertures 34
and 36 are airtightly blocked by sealing plates 35 and 37.
These evacuation apertures 34 and 36 are preferably from 1 mm to 10
mm in diameter. The peripheral edges of evacuation apertures 34 and
36 are indented portions which are indented toward the inside of
outer container 4 and upper panel 11, respectively, so that after
sealing plates 35 and 37 are fixed to outer container 4 and outer
panel 11, they do not jut out from outer container 4 and outer
panel 11. Sealing plates 35 and 37 are the same shape as the
indented portions of the peripheral edges of apertures 34 and 36,
and fit into these indented portions, and sealing plates 35 and 37
and the indented portions are unitarily joined by means of a
joining method such as adhesion by an adhesive, brazing material,
and ultrasonic welding.
Sealing plates 35 and 37 can be made from metallic materials,
synthetic resins, or the like, preferably using material of the
same quality as that of outer container 4 and outer panel 11.
As suitable adhesives for fixing sealing plates 35 and 37, epoxy
resin based adhesives and cyanoacrylate-based adhesives can be
given.
Cold-hot storage box 1B can be manufactured by basically the same
method as cold-hot storage box 1 in the aforementioned
manufacturing example. In manufacturing insulating container 2,
evacuation aperture 34 is provided in a recessed manner; the
peripheral edges of aperture 34 are indented; outer container 4 and
inner container 3 are made from metallic materials, synthetic
resins, or the like; and metallic membranes 31 and 32 are formed
onto the inner surface of outer container 4 and the outer surface
of inner container 3. The outer container 4 and inner container 3
on which metallic membranes 31 and 32 have been formed are combined
and integrated by joining. Next, the obtained double walled
container is put into a chamber, and after the air in space 5 has
been evacuated, space 5 is filled with a gas having low thermal
conductivity, such as xenon gas, to the level of about atmospheric
pressure, sealing plate 35 is fitted into the indented portion
which surrounds the edges of evacuation aperture 34, and airtightly
joined closing off evacuation aperture 34. By this sealing process,
the gas having low thermal conductivity is enclosed in space 5
forming insulation layer 6, and producing insulating container 2.
The process of vacuum evacuation of the inside of space 5 of the
double walled container and the process of filling space 5 with gas
having low thermal conductivity are preferably carried out while
adjusting the pressure of the chamber in such a way that the
difference between the pressure inside and outside the double
walled container is made small.
In the manufacturing method of insulating container 2, various
methods can be employed for the sealing process of evacuation
aperture 34 by sealing plate 35.
For example, when outer container 4 is made from metallic
materials, before the double walled container made by integrating
outer container 4 and inner container 3 is put into the chamber,
brazing material, such as solder, or the like, is put around the
indented portion of the periphery of evacuation aperture 34 and
sealing plate 35 put on. After the inside of the chamber and the
inside of space 5 of the double walled container are vacuum
evacuated, a gas having low thermal conductivity is introduced into
the chamber. Alternatively, while air is introduced into the
chamber, a gas having low thermal conductivity is introduced only
inside space 5. After space 5 has been filled up with the gas
having low thermal conductivity, the brazing material provided
between sealing plate 35 and the indented portion is heat fused,
subsequently cooled, and solidified, thereby unitarily joining
sealing plate 35 to the indented portion.
In addition, when outer container 4 is made from synthetic resin
material, the double walled container is put into the chamber, and
the inside of the chamber and the inside of space 5 of the double
walled container are vacuum evacuated. Then, a gas having low
thermal conductivity is introduced into the chamber. Alternatively,
with packing arranged at the end of a pipe, which is connected with
the outside of the chamber, pressed against the peripheral edge of
evacuation aperture 34, the double walled container is positioned
in the chamber, and after space 5 has been vacuum evacuated through
the pipe, space 5 is filled with a gas having low thermal
conductivity. After space 5 has been filled with the gas having low
thermal conductivity, adhesive is applied to the indented portion
of evacuation aperture 34, sealing plate 35 is fitted and
joined.
Door 10 is made in the same way as insulating container 2.
Cold-hot storage box 1B of the present example obtains the same
results as the aforementioned cold-hot storage box 1, in addition,
the connection of extra gas injection pipes 8 and 15 to outer
container 4 of insulating container 2 and the outer surface of
outer panel 11 of door 10 becomes unnecessary, and extra space and
a cover for protecting gas injection pipes 8 and 15 can be omitted,
making it possible to design small sized cold-hot storage box. In
addition, since it is not necessary to connect gas injection pipes
8 and 15 to outer container 4 of the insulating container and the
outer surface of outer panel 11 of door 10, the range of the choice
of design and shape for the cold-hot storage box is further
increased.
Furthermore, the aforementioned examples are not the only examples
of the present invention; it is not possible to mention all
possible embodiments. For example, the position and size of door 10
and insulating container 2 can be suitably set up to correspond to
the use of the cold-hot storage box.
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